1. Heat the olive oil in a large pot over medium heat. Add the onions and garlic, sautéing until they are fragrant and the onions are translucent, about 3-4 minutes.
2. Add the beef slices to the pot, cooking until they are browned on all sides. This should take around 5 minutes.
3. Stir in the diced tomatoes, letting them cook down until they start to break apart and release their juices, roughly 5 minutes.
4. Pour in the beef broth and water, bringing the mixture to a gentle boil. Add the soy sauce, fish sauce (if using), sugar, and black pepper. Allow the soup to simmer for 15 minutes, letting the flavors meld.
5. Add the egg noodles to the pot and cook according to the package instructions, usually about 5-7 minutes.
6. Once the noodles are cooked, slowly drizzle the beaten eggs into the soup, stirring gently to create silky ribbons.
7. Remove the pot from heat and stir in the green onions. Garnish with fresh cilantro before serving.

Cooking with my abuela taught me to trust my senses, so while these steps guide you, don’t be afraid to adjust flavors to your liking. Cooking is an act of creativity!